Catheters have been used to reach locations within a body otherwise unreachable without invasive surgery. A catheter has a distal end which is configured to enter a patient, such as a major vein, artery, or other body cavity. Once the tip of the catheter is inserted into the patient, the catheter is distally advanced until the distal end of the catheter reaches a target site.
Steerable mechanisms have been developed to facilitate the transit of catheters through a patient's blood vessels. In practice, a surgeon typically observes the catheter fluoroscopically and maneuvers the catheter by selective rotation and deflection of a steering mechanism of the proximal end of the catheter. The rotation and deflection at the proximal end bends or deflects the tip of the catheter and enables the surgeon to steer the catheter as it advances through the tortious path often found during the transit through a patient's blood vessels.
In many applications, the ability to steer the catheter is crucial to the success of a procedure and can be a factor in reducing risk to and trauma of the patient. Moreover, the ability to steer the catheter impacts the speed and ease by which the surgeon can properly position the distal end, particularly during heart mapping protocols.
The distal ends of some steerable catheters are formed of a shape memory material or structure, such as a coil spring, so that the application of a force to a steering cable (that is fixedly secured to a distal end of the catheter) deflects the distal tip of the catheter from its normal position. As the tension in the cable is released, the distal end tends to return to its normal position. The inclusion of the coil spring, cable, and other components of a steering mechanism at the distal end of the catheter imposes a limitation as to the smallest cross sectional dimension that the catheter can have. In addition, for catheters that have one or more working channels (e.g., for delivering fluids or tools), it may be difficult to secure the cable or other components of the steering mechanism to the distal end of the catheter in a way that does not interfere operations of the catheter.
Accordingly, improved devices and methods for providing access within a body would be useful.